Oral Compositions Containing Zinc, Stannous and Fluoride Ion Sources

ABSTRACT

An oral care composition containing a source of stannous ions, a source of fluoride ions and an insoluble source of zinc ions, such as zinc oxide. The composition contains an amount of citric acid sufficient to increase the level of soluble zinc ions.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The present application is continuation of U.S. application Ser. No.15/319,636, filed Dec. 16, 2016, which is a U.S. national stageapplication under 35 U.S.C. § 371 of PCT Application No.PCT/US2014/043427 filed Jun. 20, 2014, the entirety of which isincorporated herein by reference.

BACKGROUND

There is a need for agents in oral care products that provide enhancedbenefits including antibacterial, anticavity, enamel erosion prevention,breath freshening, and the like. The antibacterial effects of zinc ions,stannous ions and/or fluoride ions in the oral cavity are described inthe art and numerous attempts have been made to prepare dentifricecompositions incorporating zinc ions, stannous ions and/or fluoride ionsto take advantage of therapeutic benefits such as reduced plaque, guminflammation, gingivitis, and the like. In particular, soluble zincsalts, such as zinc citrate, have been used in dentifrice compositions.

Insoluble zinc ion sources, such as zinc oxide, have also been disclosedfor use in dentifrices, see for example US Patent ApplicationPublication 2012/0207686 (“the '686 publication”). However, use ofinsoluble zinc salts often is limited by the low levels of zinc ionsavailable for delivery to tooth surfaces, and undesirable consumerastringency when higher levels of zinc are used.

It would be desirable to provide an oral care composition which exhibitseven greater efficacy than previously-known compositions in itsprevention and/or reduction of biofilm, plaque, oral inflammation, andthe like.

BRIEF SUMMARY

The present invention relates to an oral care composition, for example adentifrice composition, that can effectively combine a stannous ionsource, a fluoride ion source, and an insoluble zinc ion source in a lowwater, preferably single phase, system that has efficacious delivery theions to the oral cavity. Stannous and zinc ions have been found to helpin the reduction/prevention of oral inflammation such as gingivitis andperiodontitis, plaque formation, oral biofilm formation, toothsensitivity, and improved breath benefits.

The present invention concerns an oral care composition comprising:

-   (a) an orally acceptable carrier;-   (b) a source of fluoride ions;-   (c) a source of stannous ions;-   (d) an insoluble source of zinc ions;-   (e) a buffering system comprising citric acid wherein the amount of    citric acid is at least 1% by weight of the composition, and    wherein the composition has a total water content of less than 15%    by weight.

In another aspect, the embodiments described herein provide a method forthe treatment and prevention of bacterial plaque accumulation comprisingadministering to the oral cavity the dentifrice composition describedabove.

It should be understood that the detailed description and specificexamples, while indicating the preferred embodiment of the invention,are intended for purposes of illustration only and are not intended tolimit the scope of the invention.

DETAILED DESCRIPTION

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material.

In this description, unless otherwise stated, the use of the singularalso includes the plural. For example, “a stannous ion source” alsocomprehends the case where more than one stannous ion source is used.

As used herein, the words “preferred” and “preferably” refer toembodiments of the invention that afford certain benefits, under certaincircumstances. However, other embodiments also may be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful, and is not intended to exclude other embodiments from the scopeof the invention.

Insoluble Zinc Ion Source

The insoluble zinc ion source in one embodiment is an insoluble zinc ionsalt. As used herein the term “insoluble” means the material or compoundhas a solubility of less than 0.1 wt. % (based on the weight of thecomposition) in a 25° C. water solution at pH 7. It also will beunderstood that at lower or higher pH, the insoluble zinc ion sourcesmay become significantly more soluble. Examples of suitable insolublezinc ion sources include zinc oxide, zinc phosphate, zinc pyrophosphate,and other zinc compounds. The insoluble zinc ion source preferably iszinc oxide.

In general, the higher the level of solubilized zinc ions available fordelivery to oral surfaces, the higher the level of efficacy. The presentinvention provides for high levels of zinc ions to be present in thecomposition from the insoluble zinc ion source. Typically, a compositionof the invention has greater than 50% soluble zinc ions (e.g. for acomposition with 1% by weight (1.0) of an insoluble zinc ion source, theamount of zinc would be greater than 0.5% (0.5) after aging for 13 weeksat 40° C.), in other embodiments greater that 60%, greater than 70%, orgreater than 80%, after aging for 13 weeks at 40° C.

The amount of zinc ion source typically will be present in an amount offrom 0.1% to 2 wt. %, by weight of the final composition. In oneembodiment, the zinc ion source is present in an amount of from 0.5 to1.5%, or from 0.9% to 1.1%.

Stannous Ion Source

The compositions of the present invention comprise a stannous ionsource. The stannous ion source can be a soluble or an insolublecompound of stannous with inorganic or organic counter ions. Examplesinclude the fluoride, chloride, chlorofluoride, acetate,hexafluorozirconate, sulfate, tartrate, gluconate, citrate, malate,glycinate, pyrophosphate, metaphosphate, oxalate, phosphate, carbonatesalts and oxides of stannous.

Oral compositions containing stannous salts, particularly stannousfluoride and stannous chloride, are described in U.S. Pat. No.5,004,597. Other descriptions of stannous salt dentifrices are found inU.S. Pat. No. 5,578,293. The preferred stannous salts are stannousfluoride and stannous chloride dihydrate. Other examples of stannoussalts include stannous acetate, stannous tartrate and sodium stannouscitrate.

In general, the higher the level of solubilized stannous ions availablefor delivery to oral surfaces, the higher the level of efficacy. Thepresent invention provides for high levels of stannous ions to bepresent in the composition from the insoluble zinc ion source.Typically, a composition of the invention has greater than 50% solublestannous ions, in other embodiments greater that 60%, greater than 70%,greater than 80%, or greater than 90% after ageing for 13 weeks at 40°C.

The stannous ion source typically will be present in an amount of from0.05% to 5%, by weight of the final composition. In one embodiment, thestannous ion source is present in an amount of from 0.1 to 1%, or from0.35% to 0.55%.

Stannous and zinc ions are derived from the ion source(s) found in theoral care composition in an effective amount. An effective amount isdefined as from at least 1000 ppm metal (zinc plus stannous) ion,preferably 2,000 ppm to 15,000 ppm. More preferably, metal ions arepresent in an amount from 3,000 ppm to 13,000 ppm and even morepreferably from 4,000 ppm to 10,000 ppm. This is the total amount ofmetal ions (stannous and zinc) that is present in the compositions fordelivery to the tooth surface.

The combined metal ion sources (stannous and zinc) typically will bepresent in an amount of from 0.15% to 7%, by weight of the finalcomposition. Preferably, the metal ion sources are present in an amountof from 0.6 to 2.5%, more preferably from 1.25% to 1.65%.

Fluoride Ion Source

The fluoride ion source herein is a fluoride source capable of providingfree fluoride ions. Soluble fluoride ion sources include sodiumfluoride, stannous fluoride, indium fluoride, zinc fluoride, and sodiummonofluorophosphate. Sodium fluoride and stannous fluoride are thepreferred soluble fluoride ion sources. U.S. Pat. No. 2,946,725 and U.S.Pat. No. 3,678,154, disclose such fluoride ion sources as well asothers.

The fluoride ion source in the present compositions preferably ispresent as a solid dispersion in the composition during storage, priorto actual brushing usage of the composition by a consumer. The level ofwater in the present compositions is too low to permit the fluoridesource to dissolve in the composition during storage. Thus, interactionbetween the fluoride ion and other ingredients such the polyphosphate,or silica if present, is minimized during storage, providing a stablecomposition during storage. When the composition is contacted by salivaand/or water at the time of brushing, the fluoride source preferablywill be dispersed and the active ion will be delivered to the oralcavity.

The present compositions may contain a soluble fluoride ion sourcecapable of providing from 50 ppm to 3500 ppm, and preferably from 500ppm to 3000 ppm of free fluoride ions. To deliver the desired amount offluoride ions, fluoride ion source may be present in the total oral carecomposition at an amount of from 0.1% to 5%, in one embodiment from 0.2%to 1%, and even from 0.3 to 0.6%, by weight of the total composition.

Buffering System

The compositions described herein also contain a buffering systemcomprising citric acid. It has been surprisingly found that an amount ofcitric acid greater than 0.6%, by weight of the oral care compositionwill result in substantially more zinc ions and or stannous ions beingpresent in the composition, from the respective zinc and/or stannous ionsources in the composition, when aged at 40° C. for 8 or 13 weeks. Insome embodiments the amount of citric acid is 0.5-4 wt. % or 1-3 wt. %,or 1.1-1.5 wt. % or 1.8-2.2 wt. % or 1.3% or 2% by weight of the oralcare composition. In one embodiment the buffering system comprisescitric acid and sodium citrate, in particular trisodium citrate.Buffering agents, as used herein, refer to agents that can be used toadjust the pH of the compositions to a range of pH 3.0 to pH 10, moretypically 6 to 8.

In addition to citric acid, other buffering agents which may optionallybe present include alkali metal hydroxides, ammonium hydroxide, organicammonium compounds, carbonates, sesquicarbonates, borates, silicates,phosphates, imidazole, and mixtures thereof. Specific buffering agentsinclude monosodium phosphate, trisodium phosphate, sodium benzoate,benzoic acid, sodium hydroxide, potassium hydroxide, alkali metalcarbonate salts, sodium carbonate, imidazole, and pyrophosphate salts.Total amounts of buffering agents typically are from 0.1% to 30%, orfrom 0.1% to 10%, or from 0.3% to 3%, by weight of the presentcomposition.

Total Water Content

Water employed in the preparation of commercially suitable oralcompositions should preferably be of low ion content and free of organicimpurities. In the dentifrice composition, water will generally compriseless than 20 wt. %, or less than 15 wt. %, or from less than 15% togreater than 10 wt. %, by weight of the composition herein. The amountsof water include the free water that is added plus that which isintroduced with other materials, such as with silica, surfactantsolutions, and/or color solutions.

Orally Acceptable Carrier

In certain embodiments, the present invention provides compositionscomprising an orally acceptable carrier or vehicle. As used herein, an“orally acceptable carrier” and “orally acceptable vehicle” are usedinterchangeably, and refer to a material or combination of materialsthat is safe for use in the present compositions, commensurate with areasonable benefit/risk ratio, with which the other ingredients may beassociated while retaining significant clinical efficacy. Such carriermaterials should be selected for compatibility with the otheringredients of the compositions, and preferably do not substantiallyreduce the efficacy of the other ingredients. Selection of specificcarrier components is dependent on the desired product form, includingdentifrices, rinses, gels, and paints.

Materials useful in carriers include but are not limited to: adhesionagents, thickening agents, viscosity modifiers, diluents, surfactants,anticalculus agents, abrasives, foam modulators, whitening agents suchas peroxides, peroxide activators, peroxide stability agents, pHmodifying agents, humectants, mouth feel agents, sweeteners, flavorants,colorants, and combinations thereof

Adhesion Agents

As used herein, an “adhesion agent” is a material or combination ofmaterials that enhances the retention of an ingredient to an oral cavitysurface onto which it is applied. Such adhesion agents include withoutlimitation: adhesives, film forming materials and viscosity enhancers;for example, hydrophilic organic polymers, hydrophobic organic polymers,silicone gums, silicone adhesives, silicas, and combinations thereof. Inone embodiment adhesive agent is a methyl vinyl ether/maleic anhydridecopolymer having an average molecular weight (M.W.) of 30,000 to1,000,000, e.g. 300,000 to 800,000. Preparation of the polymethyl vinylether-maleic anhydride copolymer is specifically set forth in U.S. Pat.Nos. 5,047,490 and 4,627,977. The polymethyl vinyl ether maleicanhydride copolymer is also commercially available under the trade nameGantrez® AN from ISP (Ashland), Wayne, N.J.

Thickening Agents

The dentifrice compositions of the present invention may incorporate oneor more thickening agents which may act as a binder system. The totalamount of thickening agent is typically from 0% to 3 wt. %, or from 0.1%to 1.5 wt. %, or from 0.2% -0.5 wt. % by weight of the oral carecomposition

One such thickening agent is polyvinylpyrrolidone (PVP), in particularcrosslinked PVP, optionally in combination with a gum such as xanthangum. Other thickening agents include polysaccharides, carbomers,poloxamers, modified celluloses, e.g., carboxymethyl cellulose (CMC),and mixtures thereof. In some embodiments these thickening agentsprovide desirable consistency and gellation to the low water oral carecomposition. It has previously been known that gelling materials thatprovide desirable rheology with water and humectant provide generallyless satisfactory rheology when the water is not present to activatetheir gellation binding properties. This is believed to be especiallytrue of glycerin humectant. The thickening agent may also compriseadditional inorganic thickening agents.

Polysaccharides, including gums, that are suitable for use herein asthickening agents include carageenans, gellan gum, locust bean gum,xanthan gum, and mixtures thereof. Carageenan is a polysaccharidederived from seaweed and has been known for use as a binder or thickenerin toothpastes, see, e.g., U.S. Pat. Nos. 6,187,293 B1 and 6,162,418.There are several types of carageenan that may be distinguished by theirseaweed source and/or by their degree of and position of sulfation.Suitable for use in the present invention are kappa carageenans,modified kappa carageenans, iota carageenans, modified iota carageenans,and mixtures thereof. Carageenans suitable for use herein include thosecommercially available from the FMC Company under the series designation“Viscarin,” including but not limited to Viscarin TP 329, Viscarin TP388, and Viscarin TP 389.

Gellan gum is another polysaccharide that is suitable for use herein. Itis a polysaccharide aerobically fermented by pseudomonas elodea. It canalso form an acceptable low water matrix when it is present at a levelof from 0.1% to 3%, preferably from 0.4% to 1.8% (w/w).

Locust bean gum and xanthan gum are also suitable polysaccharides foruse herein. Locust bean gum or xanthan gum as thickening agents can forma stable and acceptable dentifrice matrix when water level is lower than10% in the composition.

Poloxamers are also suitable as thickening agents in the low watermatrix herein. Poloxamer is a synthetic block copolymer of ethyleneoxide and propylene oxide. It is available in several types. Herein,poloxamer 407 is preferable. It can be partly dissolved in water. Whentemperature is higher than 65° C., it can dissolve in glycerin.POLOXAMER 407® is available, for example, from the BASF CORPORATION, NewJersey, USA.

Carbomers are also suitable as thickening agents in a low water matrix,especially in non-water matrix.

Modified celluloses such as hydroxyethyl cellulose and CMC are also goodthickening agents in low water matrix. Since the water level is limitedin the present compositions, modified hydroxyethyl cellulose with ahydrophobic chain (C₁₂-C₂₀) are preferred to increase the solubility andhydration of this thickening agent in other low polar solvents, such asglycerin, propylene glycol and polyethylene glycol (PEG).

The thickening agent may comprise inorganic thickening agents such ascolloidal magnesium aluminum silicate or finely divided silica tofurther improve texture. Additional inorganic thickening agents ifpresent can be used in an amount from 0.1% to 15%, more preferably from0.1% to 5%, by weight of the oral care composition.

Humectant

The humectant serves to keep toothpaste compositions from hardening uponexposure to air and certain humectants can also impart desirablesweetness of flavor to toothpaste compositions. Suitable humectants foruse in the invention include glycerin, sorbitol, polyethylene glycol,propylene glycol, xylitol, and other edible polyhydric alcohols.Preferred are glycerin, polyethylene glycol, polypropylene glycol, andmixtures thereof, especially mixtures thereof. The humectant generallycomprises from 0.1% to 70%, preferably from 1% to 60%, and morepreferably from 15% to 55%, by weight of the composition.

The humectant is believed to have a significant impact on the viscosityof the low water matrix. For example, when using polysaccharide as thethickening agent in the composition, the viscosity of the matrix willincrease when the level of glycerin or polyethylene glycol increases. Onthe contrary, the viscosity of matrix will decrease when the level ofpropylene glycol increases in the composition.

Anticalculus Agents

In various embodiments of the present invention, the oral carecomposition may comprise an anticalculus (tartar control) agent.Generally, tartar control agents are categorized as being incompatiblewith some whitening agents, but embodiments of the present inventionincorporate tartar control agents and whitening agents in a single phasewhitening composition. Suitable anticalculus agents include withoutlimitation phosphates and polyphosphates (for example pyrophosphates andtripolyphosphates), polyaminopropanesulfonic acid (AMPS),hexametaphosphate salts, zinc citrate trihydrate, polypeptides (such aspolyaspartic and polyglutamic acids), polyolefin sulfonates, polyolefinphosphates, and diphosphonates (e.g., EHDP; AHP). The oral compositionmay include a mixture of different anticalculus agents. In one preferredembodiment, tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate(STPP), tetrapotassium pyrophosphate (TKPP), or mixtures thereof areused. The anticalculus agent may comprise 0.1% to 30%. or 0.1% to 15%,or 1% to 10%, or 2% to 6%, by weight.

Abrasives

An abrasive polishing material may also be included in the toothpastecompositions. The abrasive polishing material contemplated for use inthe compositions of the present invention can be any material that doesnot excessively abrade dentin. Typical abrasive polishing materialsinclude silicas including gels and precipitates; aluminas; phosphatesincluding orthophosphates, polymetaphosphates, and pyrophosphates; andmixtures thereof. Specific examples include dicalcium orthophosphatedihydrate, calcium pyrophosphate, tricalcium phosphate, calciumpolymetaphosphate, insoluble sodium polymetaphosphate, hydrated alumina,beta calcium pyrophosphate, calcium carbonate, and resinous abrasivematerials such as particulate condensation products of urea andformaldehyde, and others such as disclosed in U.S. Pat. No. 3,070,510.Mixtures of abrasives may also be, used. If the dentifrice compositionor particular phase comprises a polyphosphate having an average chainlength of 4 or more, calcium containing abrasives and alumina are notpreferred abrasives. The most preferred abrasive is silica.

Silica dental abrasives of various types are preferred because of theirunique benefits of exceptional dental cleaning and polishing performancewithout unduly abrading tooth enamel or dentine. The silica abrasivepolishing materials herein, as well as other abrasives, generally havean average particle size ranging between 0.1 to 30 microns, andpreferably from 5 to 15 microns. The abrasive can be precipitated silicaor silica gels such as the silica xerogels described in U.S. Pat. No.3,538,230, and U.S. Pat. No. 3,862,307. Preferred are the silicaxerogels marketed under the trade name “SYLOID®” by the W. R. Grace &Company, Davison Chemical Division. Also preferred are the precipitatedsilica materials such as those marketed by the J. M. Huber Corporationunder the trade name, “ZEODENT®”, particularly the silica carrying thedesignation “Zeodent 119.” The types of silica dental abrasives usefulin the toothpastes of the present invention are described in more detailin U.S. Pat. No. 4,340,583. Silica abrasives are also described in U.S.Pat. Nos. 5,589,160; 5,603,920; 5,651,958; 5,658,553; and 5,716,601. Theabrasive in the oral care compositions described herein is generallypresent at a level of from 6% to 70% by weight of the composition.Preferably, toothpastes contain from 10% to 50% of abrasive, by weightof the composition.

Peroxide Source

The present invention may include a peroxide source in the composition.The peroxide source is selected from the group consisting of hydrogenperoxide, calcium peroxide, urea peroxide, and mixtures thereof. Thepreferred peroxide source is calcium peroxide. The following amountsrepresent the amount of peroxide raw material, although the peroxidesource may contain ingredients other than the peroxide raw material. Thepresent composition may contain from 0.01% to 10%, preferably from 0.1%to 5%, more preferably from 0.2% to 3%, and most preferably from 0.3% to0.8% of a peroxide source, by weight of the dentifrice composition.

Alkali Metal Bicarbonate Salt

The compositions also may include an alkali metal bicarbonate salt.Alkali metal bicarbonate salts are soluble in water and unlessstabilized, tend to release carbon dioxide in an aqueous system. Sodiumbicarbonate, also known as baking soda, is the preferred alkali metalbicarbonate salt. The alkali metal bicarbonate salt also functions as abuffering agent. The present composition may contain from 0.5% to 50%,preferably from 0.5% to 30%, more preferably from 2% to 20%, and mostpreferably from 5% to 18% of an alkali metal bicarbonate salt, by weightof the dentifrice composition.

Surfactants

The compositions also may comprise surfactants, also commonly referredto as sudsing agents. Suitable surfactants are those that are reasonablystable and foam throughout a wide pH range. The surfactant may beanionic, nonionic, amphoteric, zwitterionic, cationic, or mixturesthereof. Anionic surfactants useful herein include the water-solublesalts of alkyl sulfates having from 8 to 20 carbon atoms in the alkylradical (e.g., sodium alkyl sulfate) and the water-soluble salts ofsulfonated monoglycerides of fatty acids having from 8 to 20 carbonatoms. Sodium lauryl sulfate and sodium coconut monoglyceride sulfonatesare examples of anionic surfactants of this type. Other suitable anionicsurfactants are sarcosinates, such as sodium lauroyl sarcosinate,taurates, sodium lauryl sulfoacetate, sodium lauroyl isethionate, sodiumlaureth carboxylate, and sodium dodecyl benzenesulfonate. Mixtures ofanionic surfactants can also be employed. Many suitable anionicsurfactants are disclosed in U.S. Pat. No. 3,959,458.

Nonionic surfactants that can be used in the compositions can broadly bedefined as compounds produced by the condensation of alkylene oxidegroups (hydrophilic in nature) with an organic hydrophobic compoundwhich may be aliphatic or alkyl-aromatic in nature. Examples of suitablenonionic surfactants include poloxamers (sold under trade namePLURONIC®), polyoxyethylene, polyoxyethylene sorbitan esters (sold undertrade name TWEENS®), Polyoxyl 40 hydrogenated castor oil, fatty alcoholethoxylates, polyethylene oxide condensates of alkyl phenols, productsderived from the condensation of ethylene oxide with the reactionproduct of propylene oxide and ethylene diamine, ethylene oxidecondensates of aliphatic alcohols, long chain tertiary amine oxides,long chain tertiary phosphine oxides, long chain dialkyl sulfoxides, andmixtures of such materials. The amphoteric surfactants useful in thepresent invention can be broadly described as derivatives of aliphaticsecondary and tertiary amines in which the aliphatic radical can be astraight chain or branched and wherein one of the aliphatic substituentscontains from 8 to 18 carbon atoms and one contains an anionicwater-solubilizing group, e.g., carboxylate, sulfonate, sulfate,phosphate, or phosphonate. Other suitable amphoteric surfactants arebetaines, specifically cocamidopropyl betaine. Mixtures of amphotericsurfactants can also be employed. Many of these suitable nonionic andamphoteric surfactants are disclosed in U.S. Pat. No. 4,051,234. Thepresent composition typically comprises one or more surfactants each ata level of from 0.25% to 12%, preferably from 0.5% to 8%, and mostpreferably from 1% to 6%, by weight of the composition.

In an embodiment, the oral care composition includes a surfactant systemcomprising sodium laurel sulfate (SLS), cocamidopropyl betaine, or amixture thereof.

Antimicrobial Agents

The present compositions may also include antimicrobial agents. Includedamong such agents are water insoluble non-cationic antimicrobial agentssuch as halogenated diphenyl ethers, phenolic compounds including phenoland its homologs, mono and poly-alkyl and aromatic halophenols,resorcinol and its derivatives, bisphenolic compounds and halogenatedsalicylanilides, benzoic esters, and halogenated carbanilides,polyphenols, and herbals. The water soluble antimicrobials includequaternary ammonium salts and bis-biquanide salts, among others.Triclosan monophosphate is a preferred additional water solubleantimicrobial agent. The quaternary ammonium agents include those inwhich one or two of the substitutes on the quaternary nitrogen has acarbon chain length (typically alkyl group) from 8 to 20, typically from10 to 18 carbon atoms while the remaining substitutes (typically alkylor benzyl group) have a lower number of carbon atoms, such as from 1 to7 carbon atoms, typically methyl or ethyl groups. Dodecyl trimethylammonium bromide, tetradecylpyridinium chloride, domiphen bromide,N-tetradecyl-4-ethyl pyridinium chloride, dodecyl dimethyl(2-phenoxyethyl) ammonium bromide, benzyl dimethylstearyl ammoniumchloride, cetyl pyridinium chloride, quaternized5-amino-1,3-bis(2-ethyl-hexyl)-5-methyl hexa hydropyrimidine,benzalkonium chloride, benzethonium chloride and methyl benzethoniumchloride are exemplary of typical quaternary ammonium antibacterialagents. Other compounds are bis[4-(R-amino)-1-pyridinium]alkanes asdisclosed in U.S. Pat. No. 4,206,215, issued Jun. 3, 1980, to Bailey.

Other antimicrobials such as copper bisglycinate, copper glycinate, zinccitrate, and zinc lactate may also be included. Also useful are enzymes,including endoglycosidase, papain, dextranase, mutanase, and mixturesthereof. Such agents are disclosed in U.S. Pat. No. 2,946,725 and inU.S. Pat. No. 4,051,234. Specific antimicrobial agents includechlorhexidine, triclosan, triclosan monophosphate, and flavor oils suchas thymol. Triclosan is a preferred antimicrobial agent for inclusion inthe present compositions. Triclosan and other agents of this type aredisclosed in U.S. Pat. No. 5,015,466 and U.S. Pat. No. 4,894,220. Theseagents may be present at levels of from 0.01% to 1.5%, by weight of thecomposition.

Titanium dioxide may also be added to the present composition. Titaniumdioxide is a white powder which adds opacity to the compositions.Titanium dioxide generally comprises from 0.25% to 5%, by weight of thecomposition.

Coloring agents may also be added to the present composition. Thecoloring agent may be in the form of an aqueous solution, preferably 1%coloring agent in a solution of water. Color solutions generallycomprise from 0.01% to 5%, by weight of the composition.

A flavor system can also be added to the compositions. Suitableflavoring components include oil of wintergreen, oil of peppermint, oilof spearmint, clove bud oil, menthol, anethole, methyl salicylate,eucalyptol, cassia, 1-menthyl acetate, sage, eugenol, parsley oil,oxanone, alpha-irisone, marjoram, lemon, orange, propenyl guaethol,cinnamon, vanillin, ethyl vanillin, heliotropine, 4-cis-heptenal,diacetyl, methyl-para-tert-butyl phenyl acetate, and mixtures thereof.Coolants may also be part of the flavor system. Preferred coolants inthe present compositions are the paramenthan carboxyamide agents such asN-ethyl-p-menthan-3-carboxamide (known commercially as “WS-3”) andmixtures thereof. A flavor system is generally used in the compositionsat levels of from 0.001% to 5%, by weight of the composition.

Sweetening agents can be added to the compositions. These includesaccharin, dextrose, sucrose, lactose, xylitol, maltose, levulose,aspartame, sodium cyclamate, D-tryptophan, dihydrochalcones, acesulfame,and mixtures thereof. Various coloring agents may also be incorporatedin the present invention. Sweetening agents and coloring agents aregenerally used in toothpastes at levels of from 0.005% to 5%, by weightof the composition.

A herbal agent, including but not limited to, golden thread extract,honeysuckle extract, and mixtures thereof, may also be present in thecompositions herein at levels of from 0.01% to 0.05%. Such herbal agentsare believed to provide anti-bacterial efficacy. Polyphenols may furtherbe included at levels from 0.01% to 2%. A preferred polyphenol is teapolyphenol.

An effective amount of a desensitizing agent may also be incorporatedinto the present compositions. The desensitizing agents include thoseselected from alkaline metal salts with a chloride, nitrate sulfate, oracetate of a group II metal or aluminum or polymerizable monomer toocclude the tubules, alkaline metal or ammonium nitrate, ammoniumoxylate, citric acid and sodium citrate. Preferred salts are potassiumnitrate, potassium citrate, and mixtures thereof. Such desensitizingagents are disclosed in e.g., U.S. Pat. No. 5,718,885.

A stain reducing agent such as Plasdone S-630 or aluminum hydrate mayfurther be added to the composition. Plasdone is polyvinyl pyrrolidone(PVP) that can be synthesized by polymerizing vinylpyrrolidone.Commercially, it has been produced as a series of products having meanmolecular weights ranging from 10,000 to 700,000. Herein, the lowmolecular weights and middle molecular weights (from 10,000 to 100,000)are preferred. In order to remove stain effectively, the level of PVP ispreferably from 0.5% to 10%, more preferably from 1.0% to 7.0%, and evenmore preferably from 1.5% to 5.0%.

The compositions of the present invention optionally comprise anutrient. Suitable nutrients include vitamins, minerals, amino acidssuch as L-arginine, and mixtures thereof. Vitamins include Vitamins Cand D, thiamine, riboflavin, calcium pantothenate, niacin, folic acid,nicotinamide, pyridoxine, cyanocobalamin, para-aminobenzoic acid,bioflavonoids, and mixtures thereof. Nutritional supplements includeamino acids (such as L-tryptophane, L-lysine, methionine, threonine,levocarnitine and L-carnitine), lipotropics (such as choline, inositol,betaine, and linoleic acid), and mixtures thereof.

It is understood that while general attributes of each of the abovecategories of materials may differ, there may be some common attributesand any given material may serve multiple purposes within two or more ofsuch categories of materials. All of the ingredients in the compositionsmay have functions in addition to their primary function, and maycontribute to the overall properties of the composition, including itsstability, efficacy, consistency, mouthfeel, taste, odor and so forth.Preferably, the carrier ingredients are selected for compatibility withother ingredients of the composition.

A type of product form of the present invention is a dentifrice. Theterm “dentifrice” generally denotes formulations which are used to cleanthe surfaces of the oral cavity. The dentifrice is an oral compositionthat is not intentionally swallowed for purposes of systemicadministration of therapeutic agents, but is applied to the oral cavity,used to treat the oral cavity and then expectorated. Typically thedentifrice is used in conjunction with a cleaning implement such as atoothbrush, usually by applying it to the bristles of the toothbrush andthen brushing the accessible surfaces of the oral cavity. Preferably thedentifrice is in the form of a paste or a gel (or a combination thereof)

The oral care compositions of the invention are typically in a singlephase. However, in some embodiments, components are physicallyseparated, for example by using a dual compartmented package. Thedentifrice compositions may be a paste, gel, or any configuration orcombination thereof. A further embodiment of the present inventionincludes dual-phase or multi-phase compositions comprising the presentlow-water compositions as one phase and at least one other separatephase comprising additional dentifrice components to further enhancestability, performance and/or aesthetics of the dentifrice product. Forexample, a dual phase composition may comprise a first phase comprisingthe present low-water composition with polyphosphate and ionic active(s)and a separate second phase comprising additional active agents such asbleaching agents, preferably a peroxide source, or a tooth surfaceconditioning agent to provide improved cleaning, whitening,anti-staining and mouth feel benefits. Examples of tooth conditioningagents are polysiloxanes and modified polysiloxanes, includingdiorganopolysiloxanes such as polydimethylsiloxane (PDMS); alkyl- andalkoxy-dimethicone copolyols such as C₁₂ to C₂₀ alkyl dimethiconecopolyols; and aminoalkylsilicones. These siloxane polymers aredescribed for example in U.S. Pat. Nos. 5,759,523; 6,024,891; 6,123,950;6,019,962; and 6,139,823.

The dispenser for the dentifrice compositions may be a tube, pump, orany other container suitable for dispensing toothpaste. In a dual phaseoral composition, each oral composition will be contained in aphysically separated compartment of a dispenser and dispensedside-by-side.

Methods of Use

In practicing the embodiments, the user need only apply the oral carecomposition herein, to the tooth surfaces of a human or animal, in theareas desired, in order to obtain a desired effect, e.g., plaquereduction or prevention, whitening, breath freshening, cariesprevention, pain relief, gum health, tartar control, erosion control,etc. Use of dentifrices to control erosion of the tooth surface, or toprevent demineralization, are known and described in, for example, U.S.Pat. No. 6,685,920. The compositions also may be applied to other oralcavity surfaces, such as the gingival or mucosal tissues, although it isbelieved that the benefits are best achieved when the dentifricecompositions are applied to the teeth. The dentifrice composition maycontact the tooth and/or oral cavity surface either directly, orindirectly, however, it is preferred that the dentifrice composition bedirectly applied. The dentifrice composition may be applied by anymeans, but is preferably applied with a brush or by rinsing with adentifrice slurry. The application may be at least once a day, althoughup to five times per day may be preferred, and may be carried out over aduration of time, e.g., one week, up to one year, up to three years orfor a lifetime

The manufacture of the oral composition of the present invention may beaccomplished by any of the various standard techniques for producingsuch compositions. For example, preparation methods for dentifrices arewell known, for example, as described in U.S. Pat. No. 3,966,863; U.S.Pat. No. 3,980,767; U.S. Pat. No. 4,328,205; and U.S. Pat. No.4,358,437. To make a dentifrice, a vehicle may be prepared containinghumectant, for example, one or more of glycerin, glycerol, sorbitol, andpropylene glycol, thickener agents and antibacterial agent such astriclosan, and the vehicle and a mixture of anionic and amphotericsurfactants are added, followed by blending in of a polishing agent, aswell as fluoride salts, with the pre-mix. Finally, flavoring agent, isadmixed and the pH is adjusted to between 6.8 to 7.0.

Some embodiments of the present invention provide an oral carecomposition (Composition 1) comprising:

-   -   (a) an orally acceptable carrier;    -   (b) a source of fluoride ions;    -   (c) a source of stannous ions;    -   (d) an insoluble source of zinc ions;    -   (e) a buffering system comprising citric acid wherein the amount        of citric acid is at least 1% by weight of the composition, and        wherein the composition has a total water content of less than        15% by weight, for example:    -   1.1. Composition 1 wherein the amount of citric acid is 0.5-4        wt. % or 1-3 wt. %, or 1.1-1.5 wt. % or 1.8-2.2 wt. % or 1.3% or        2% by weight.    -   1.2. Any of the foregoing compositions wherein the insoluble        source of zinc ions comprises a zinc salt of an organic acid;    -   1.3. Any of the foregoing compositions wherein the insoluble        source of zinc ions comprises zinc oxide, zinc phosphate, zinc        pyrophosphate or a mixture thereof;    -   1.4. Any of the foregoing compositions wherein the fluoride ion        source is a salt selected from stannous fluoride, sodium        fluoride, potassium fluoride, sodium monofluorophosphate, sodium        fluorosilicate, ammonium fluorosilicate, amine fluoride (e.g.,        N′-octadecyltrimethylendiamine-N,N,N′-tris(2-ethanol)-dihydrofluoride),        ammonium fluoride, titanium fluoride, hexafluorosulfate, and        combinations thereof;    -   1.5. Any of the foregoing compositions wherein the stannous ion        source is selected from stannous fluoride, stannous chloride        dehydrate, stannous acetate, stannous tartrate, sodium stannous        citrate, or a mixture thereof;    -   1.6. Any of the foregoing compositions wherein the source of        fluoride ions and the source of stannous ions comprises stannous        fluoride;    -   1.7. Any of the foregoing compositions comprising at least one        polyphosphate salt selected from the group consisting of        inorganic polyphosphate salts which have equal to or less than        three phosphorous atoms    -   1.8. Composition 1.5 wherein the at least one polyphosphate is        selected from the group consisting of tetrasodium pyrophosphate,        sodium tripolyphosphate, and mixtures thereof; wherein the total        polyphosphate comprises from 1 to 10 wt % of the composition;    -   1.9. Any of the foregoing compositions wherein the buffering        system comprises a mixture of citric acid and trisodium citrate;    -   1.10. Any of the foregoing compositions comprising a thickening        agent which comprises, in combination, cross-linked        polyvinylpyrrolidone and a gum;    -   1.11. Any of the foregoing compositions comprising a thickening        agent which comprises a cellulose, a synthetic block copolymer        of ethylene oxide and propylene oxide, or a mixture thereof;    -   1.12. Any of the foregoing compositions wherein the zinc ion        source is present in an amount of from 0.1 to 2 wt. %, or from        0.5% to 1.5 wt. % or from 0.9% to 1.1 wt. %; 1.13. Any of the        foregoing compositions wherein the stannous ion source is        present in an amount of from 0.05% to 5% wt., or from 0.1% to 1%        wt.; or from 0.35-0.55 wt. %    -   1.14. Any of the foregoing compositions wherein the amount        fluoride ion source is from 0.1% to 5%, or from 0.2% to 1%, or        from 0.3 to 0.6%, by weight of the total composition;    -   1.15. Any of the foregoing compositions wherein the composition        has a total water content of less than 20%, or less than 15%, or        from less than 15% to greater than 10 wt. %, based on the weight        of the composition;    -   1.16. Any of the foregoing compositions wherein combined metal        ion source is present in an amount of from 0.15% to 7%, by        weight, or from 0.6 to 2.5%, or from 1.25% to 1.65%, by weight        of the composition;    -   1.17. Any of the foregoing compositions comprising a methyl        vinyl ether/maleic anhydride copolymer having an average        molecular weight (M.W.) of 30,000 to 1,000,000, e.g. 300,000 to        800,000;    -   1.18. Any of the foregoing compositions comprising L-arginine in        free or orally acceptable salt form;    -   1.19. Any of the foregoing compositions comprising additional        buffering agents, e.g., sodium phosphate buffer (e.g., sodium        phosphate monobasic and disodium phosphate);    -   1.20. Any of the foregoing compositions comprising a humectant,        e.g., selected from, sorbitol, propylene glycol, polyethylene        glycol, xylitol, and mixtures thereof;    -   1.21. Any of the foregoing compositions further comprising an        abrasive or particulate;    -   1.22. The foregoing composition wherein the abrasive or        particulate is selected from sodium bicarbonate, calcium        phosphate (e.g., dicalcium phosphate dihydrate), calcium        sulfate, precipitated calcium carbonate, silica (e.g., hydrated        silica), iron oxide, aluminum oxide, perlite, plastic particles,        e.g., polyethylene, and combinations thereof;    -   1.23. Any of the foregoing compositions comprising an abrasive        in an amount of 15 wt. % to 70 wt. % of the total composition        weight;    -   1.24. Any of the foregoing compositions comprising one or more        surfactants, e.g., selected from anionic, cationic,        zwitterionic, and nonionic surfactants, and mixtures thereof,        e.g., comprising an anionic surfactant, e.g., a surfactant        selected from sodium lauryl sulfate, sodium ether lauryl        sulfate, and mixtures thereof, e.g. in an amount of from 0.3% to        4.5% by weight;    -   1.25. Any of the foregoing compositions further comprising one        or more polymers selected from polyethylene glycols,        polysaccharides (e.g., cellulose derivatives, for example        carboxymethyl cellulose, polysaccharide gums, for example        xanthan gum or carrageenan gum), and combinations thereof;    -   1.26. Any of the foregoing compositions comprising one or more        antibacterial agents, for example comprising an antibacterial        agent selected from halogenated diphenyl ether (e.g. triclosan),        herbal extracts and essential oils (e.g., rosemary extract, tea        extract, magnolia extract, thymol, menthol, eucalyptol,        geraniol, carvacrol, citral, hinokitol, catechol, methyl        salicylate, epigallocatechin gallate, epigallocatechin, gallic        acid, miswak extract, sea-buckthorn extract), bisguanide        antiseptics (e.g., chlorhexidine, alexidine or octenidine),        quaternary ammonium compounds (e.g., cetylpyridinium chloride        (CPC), benzalkonium chloride, tetradecylpyridinium chloride        (TPC), N-tetradecyl-4-ethylpyridinium chloride (TDEPC)),        phenolic antiseptics, hexetidine, octenidine, sanguinarine,        povidone iodine, delmopinol, salifluor, metal ions (e.g., zinc        salts, for example, zinc citrate, stannous salts, copper salts,        iron salts), sanguinarine, propolis and oxygenating agents        (e.g., hydrogen peroxide, buffered sodium peroxyborate or        peroxycarbonate), phthalic acid and its salts, monoperthalic        acid and its salts and esters, ascorbyl stearate, oleoyl        sarcosine, alkyl sulfate, dioctyl sulfosuccinate,        salicylanilide, domiphen bromide, delmopinol, octapinol and        other piperidino derivatives, nicin preparations, chlorite        salts; and mixtures of any of the foregoing; e.g., comprising        triclosan or cetylpyridinium chloride;    -   1.27. Any of the foregoing compositions comprising a whitening        agent, e.g., a selected from the group consisting of peroxides,        metal chlorites, perborates, percarbonates, peroxyacids,        hypochlorites, and combinations thereof;    -   1.28. Any of the foregoing compositions further comprising        hydrogen peroxide or a hydrogen peroxide source, e.g., urea        peroxide or a peroxide salt or complex (e.g., such as        peroxyphosphate, peroxycarbonate, perborate, peroxysilicate, or        persulphate salts; for example calcium peroxyphosphate, sodium        perborate, sodium carbonate peroxide, sodium peroxyphosphate,        and potassium persulfate);    -   1.29. Any of the foregoing compositions further comprising a        source of calcium and phosphate selected from (i) calcium-glass        complexes, e.g., calcium sodium phosphosilicates, and (ii)        calcium-protein complexes, e.g., casein phosphopeptide-amorphous        calcium phosphate;    -   1.30. Any of the foregoing compositions further comprising a        soluble calcium salt, e.g., selected from calcium sulfate,        calcium chloride, calcium nitrate, calcium acetate, calcium        lactate, and combinations thereof;    -   1.31. Any of the foregoing compositions further comprising a        physiologically or orally acceptable potassium salt, e.g.,        potassium nitrate or potassium chloride, in an amount effective        to reduce dentinal sensitivity;    -   1.32. Any of the foregoing compositions in the form of a        dentifrice, for example a toothpaste, e.g., a clear gel or        opaque toothpaste;    -   1.33. Any of the foregoing compositions in the form of a single        phase;    -   1.34. Any of the foregoing compositions comprising one or more        of the following in the recited amounts:

Citric acid 0.5-3 or 1.1-1.5 or 1.8-2.2 wt. % Trisodium citrate 0.5-10or 1-6 or 2-4 or 2.9-3.1 wt % Zinc oxide 0.1-5 or 0.5-2 or 0.9-1.1 wt %Stannous fluoride 0.1-5, or 0.1-2, or 0.4-0.6% wt % Glycerin 10-50 wt %Propylene glycol 1-25, or 2-10, or 6-8 wt % Xantham gum 0.1-12 or 0.1-1,or 0.1-.0.5 or 0.275-0.325 wt % polyvinylpyrrolidone 0.25-10 wt % CMC0.2-1.5 or 0.3-0.9 or 0.65-0.75% Silica (total) 5-60 or 10-50, or 10-40or 22-26 wt % Tetrasodium 0.1-10 or 0.5-5 or 1-4 or 1.75-2.25 wt %Pyrophosphate (TSPP) Sodium acid 0-5 or 0-3 or 0.5-1.5 or 0.9-1.1 wt %pyrophosphate (SAPP) Sodium 0.1-10, or 0.5-5 or 1-4, or 2.75-3.25 wt %Tripolyphosphate (STPP) Sodium lauryl 0.1-10, or 0.2-5, or 1.2-2.5 or1.5-1.75 wt % sulfate (SLS) Cocamidopropyl 0.1-10, or 0.5-5 or 0.5-2 or0.75 to 1.25 wt % betaine

-   -   1.35. Any of the foregoing compositions which does not contain        methylvinyl ether-maleic anhydride copolymer;    -   1.36. A method of treating or preventing a disease or condition        of the oral cavity comprising contacting an oral cavity surface        of a patient in need thereof with the composition of any one of        the foregoing compositions;    -   1.37. Any of the foregoing methods which is a method for the        treatment and prevention of bacterial plaque accumulation or        prevention of tooth erosion.

The following examples are further illustrative of the preferredembodiments, but it is understood that the invention is not limitedthereto.

EXAMPLES Example 1 Procedure

Four formulations are prepared with the ingredients indicated forFormula A, with the amounts of CMC and citric acid, TKPP, SAPP and STPPvaried as indicated in Tables 1 and 2.

The technique to determine water soluble tin and water soluble zinc inthe formulations is by flame atomic absorption spectroscopy (FAAS). Asuitable double beam atomic absorption spectrophotometer fitted with anair-acetylene burner and deuterium background correction, e.g. VarianSpectrAA 220FS, can be used. Also, a suitable zinc hollow cathode lampand AA grade acetylene can be used. Water soluble zinc or tin can bemeasured in the compositions by FAAS after dilution of a sample in waterand comparing to zinc or tin standards. A portion of the formulation isdispersed with water, solutions are transferred to a volumetric flask,diluted to volume with water and centrifuged. Tin or zinc is detected inthe supernatant by atomic absorption spectroscopy and quantitated bycomparing the absorbance of the sample solution to absorbances ofexternal calibration standards of known tin or zinc concentration. Todetermine total tin or zinc, rather than dispersing the samples inwater, the samples are digested with a suitable acid mixture, e.g.,hydrochloric, nitric, and or hydrofluoric, over a steam bath.

The formulas are aged at 40° C. for up to 13 weeks. The total tin, totalzinc, soluble tin and soluble zinc levels are determined at various timepoints.

TABLE 1 Product Test Initial 4 wk 8 wk 13 wk 0% CMC + 1.3% Soluble Tin0.25 0.12 0.09 0.17 Citric Acid Soluble Zinc 0.69 0.68 0.57 0.55 TotalTin 0.35 — — — Total Zinc 0.96 — — — pH (as is) 5.73 6.53 6.56 6.61 10%pH 7.96 8.05 7.88 7.89 0.4% CMC + 1.3% Soluble Tin 0.25 0.12 0.1  0.11Citric Acid Soluble Zinc 0.68 0.66 0.59  0.625 Total Tin 0.35 — — —Total Zinc 0.92 — — — pH (as is) 6.1 6.89 6.78 6.93 10% pH 8.02 7.777.77 7.65 0% CMC + 2% Soluble Tin 0.33 0.28 0.29 0.34 Citric AcidSoluble Zinc 0.64 0.7  0.62 0.6  Total Tin 0.34 — — — Total Zinc 0.72 —— — pH (as is) 5.32 5.9  5.96 5.98 10% pH 6.77 6.83 6.81 6.84 0.4% CMC +2% Soluble Tin 0.35 0.33 0.35 0.32 Citric Acid Soluble Zinc 0.62 0.630.54 0.63 Total Tin 0.37 — — — Total Zinc 0.76 — — — pH (as is) 5.9 6.076.11 6.13 10% pH 6.67 6.75 6.74 6.67

TABLE 2 Percent Zinc Soluble Initial 4 wk 8 wk 13 wk Sn + ZnO + 1.3%Citric 71.88% 70.83% 59.38% 57.29% Acid + 0% CMC Sn + ZnO + 1.3% Citric73.91% 71.74% 64.13% 67.93% Acid + 0.4% CMC Sn + ZnO + 2.0% Citric88.89% 97.22% 86.11% 83.33% Acid + 0% CMC Sn + ZnO + 2.0% Citric 81.58%82.89% 71.05% 82.89% Acid + 0.4% CMC

-   -   Solubility of Stannous Fluoride: 31 g/100mL (0° C.), 35 g/100 mL        (20° C.)

Formula A Ingredient Weight % Demineralized Water 10 Sodium Saccharin0.6 Trisodium Citrate Dihydrate 3 Citric Acid-Anydrous 1.3-2   StannousFluoride 0.45 Zinc Oxide 1 Tetrasodium Pyrophosphate 0-2 SodiumTripolyphosphate 0-3 99.0%-101.0% Glycerin balance Polyethylene Glycol600 3 Propylene Glycol 4 PVP 1 Dye <0.01 Titanium Dioxide Coated Mica0.15 Xanthan Gum 0.3 Carboxymethyl Cellulose (CMC 7)   0-0.4 Syn.Amorph. PPT. Silica-Abrasive 12 High Cleaning Silica 12 Sodium LaurylSulfate Powder 1.75 Cocamidopropyl Betaine 1 Flavor 1.4 Total 100

Results Comparative Example

Earlier work with a formula comprising a soluble zinc source (2 wt. %zinc citrate) and 0.454 wt. % stannous fluoride with 0.6 wt. % citricacid/3.0 wt. % trisodium citrate. This formula had an initial amount ofsoluble zinc of only 0.39 wt. % which decreased slightly to 0.34 wt. %after 12 weeks of aging. The amount of stannous remained steady from itsinitial solubility to the end of the 12 week aging period (ranging from0.31 wt. %-0.36 wt. %).

Surprisingly, formulas with or without CMC with the same amount (0.454wt. %) stannous fluoride and a lesser amount (1 wt. %) of less solublezinc source (ZnO) showed greater initial solubility when greater than 1wt. % citric acid was used (ranging from 0.62 wt. % to 0.69 wt. %) andthis higher level of solubility was maintained despite 13 weeks of aging(0.55 wt. % to 0.63 wt. %).

Furthermore, when the amount of citric acid was increased to 2%, theinitial amount of soluble stannous and amount after 13 weeks of aging(0.32 wt. % to 0.35 wt. %) was comparable to the ranges measured in theComparative Example.

As those skilled in the art will appreciate, numerous changes andmodifications may be made to the embodiments described herein withoutdeparting from the spirit of the invention. It is intended that all suchvariations fall within the scope of the appended claims.

1. An oral care composition comprising in a single phase: (a) an orallyacceptable vehicle; (b) a source of fluoride ions; (c) a source ofstannous ions; (d) an insoluble source of zinc ions; (e) a bufferingsystem comprising citric acid wherein the amount of citric acid is0.5-4% by weight of the composition, and wherein the composition has atotal water content of less than 15% by weight, based on the weight ofthe composition. 2-5. (canceled)
 6. The composition of claim 1 whereinthe insoluble source of zinc ions comprises a zinc salt of an organicacid.
 7. The composition of claim 3, wherein the insoluble source ofzinc ions comprises zinc oxide, zinc phosphate, zinc pyrophosphate or amixture thereof.
 8. The composition of claim 1 wherein the source offluoride ions and the source of stannous ions comprises stannousfluoride.
 9. The composition of claim 1 comprising at least onepolyphosphate salt selected from the group consisting of inorganicpolyphosphate salts which have equal to or less than three phosphorousatoms.
 10. The composition of claim 6, wherein the at least onepolyphosphate is selected from the group consisting of tetrasodiumpyrophosphate, sodium tripolyphosphate, and mixtures thereof; whereinthe total polyphosphate comprises from 1 to 10 wt % of the composition11. The composition of claim 1 wherein the buffering system comprises amixture of citric acid and trisodium citrate.
 12. The composition ofclaim 1 comprising polyvinylpyrrolidone, a gum, or a mixture thereof.13. The composition of claim 1 comprising a modified cellulose such ascarboxymethyl cellulose.
 14. The composition of claim 1 furthercomprising at least one humectant selected from the group consisting ofglycerin, polyethylene glycol, propylene glycol, and mixtures thereof.15. The composition of claim 1 wherein the composition is a dentifricecomprising one or more of an abrasive, a surfactant, a foaming agent, avitamin, a polymer, a whitening agent, an enzyme, a humectant, athickener, an antimicrobial agent, a preservative, L-arginine, aflavoring, or a coloring agent.
 16. The composition of claim 1 in asingle phase.
 17. An oral care composition comprising: (a) 0.5-3 wt. %citric acid; (b) 0.5-10 wt % Trisodium citrate; (c) 0.1-5 wt % Zincoxide; (d) 0.1-5 wt % Stannous fluoride; (e) 10-50 wt % Glycerin; (f)1-25 wt. % Propylene glycol; optionally comprising one or more of: (g)0.1-12 wt % xanthan gum; (h) 0.25-10 wt % polyvinylpyrrolidone (PVP);(i) 0.2-1.5% wt. % carboxymethylcellulose (CMC); (j) 5-60 wt % Silica(total); (k) 0.1-10 wt % Tetrasodium Pyrophosphate (TSPP); (l) 0- 5 wt %Sodium acid pyrophosphate (SAPP); (m) 0.1-10 wt % SodiumTripolyphosphate (STPP); (n) 0.1-10 wt % Sodium lauryl sulfate (SLS);(o) 0.1-10 wt % Cocamidopropyl betaine. 18-19. (canceled)
 20. A methodof treating or preventing a disease or condition of the oral cavitycomprising contacting an oral cavity surface of a patient in needthereof with the composition of claim 1 any one of the foregoing claims.21. The method of claim 20, wherein the disease or condition of the oralcavity is biofilm formation, plaque formation, oral inflammation or acombination thereof